I switched to a new provider yesterday, and I'm gonna receive an iPhone 5s from them later today. But as the cancellation of my plan with the previous provider isn't completed yet, the SIM card coming with the phone will use a temporary number. As soon as my old provider is ready, my current number will be transferred to the new SIM. This requires no action on my part; the SIM will simply be "offline" for a few hours and will then use my current number.

I was wondering if the iPhone and also iTunes will display the changed number immediately or if there's anything I have to do. For example, restarting the phone, removing and re-inserting the SIM, or even restoring the phone?

Are there any other consequences of a changed number I should be aware of? Because if it's a hassle, I'd rather wait until the number is transferred before I actually unbox the phone.